Investigations of interferences in graphite furnace atomic-absorption spectrometry using a dual cavity platform. Part 1. Influence of nickel chloride on the determination of antimony

Abstract

Analyte and interferent are volatilised from separated spots of a L'vov platform with two cavities. The results obtained give a deeper insight into the mechanisms of interferences observed in a graphite tube furnace. Losses of the analyte element in a molecular form during volatilisation of the matrix or, in general, during pre-atomisation treatment steps are found to be dominant when antimony and nickel chloride are mixed. Pronounced interactions between the gas phase and the condensed phase are observed, however, when the analyte and interferent are separated on the dual cavity platform. Essentially, all interferences disappear when nickel in nitric acid is used as a matrix modifier and proper conditions are selected. The absence of any gas-phase interactions allows the conclusion that near thermal equilibrium is obtained under these conditions. The characteristic mass found for antimony was typically between 25 and 30 pg per 0.0044 A s.